Arm chair



FIG. 1 is a perspective view of an arm chair showing our new design;

FIG. 2 is a front perspective view thereof;

FIG. 3 is a right side perspective view thereof, the left side being a mirror image of the right side; and,

FIG. 4 is a top plan view thereof.

The surfaces or portions of the article not shown in the Figures or described in the specification form no part of the claimed design. 

The ornamental design for a arm chair, as shown and described. 